Vapor generator



E. LQDAMAN VAPOR GENERATOR Oct. 47, 1958 Filed Oct. 25; 1955 E. L. DAMAN VAPOR GENERATOR Oct. 7, 1958 Filed Oct. 25, 1955 4 Sheets-Sheet 2 on@ 7, 195s E; L. @AMAN 2,854,961

VAPOR GENERATOR Filed Oct. 25, 1955 4 Sheets-Sheet 3 @y @JLM ATTORNEY Oct. 7, 1958 E. L. DAMAN 2,854,961

l VAPOR GENERATOR Filed Oct. 25, 1955 4 Sheets-Sheet 4 ATTORNEY United States Patent vOffice varon GENERATOR Ernest L. Daman, Westfield, N. J.,

Wheeler Corporation, of New York assigner to Foster New York, N. Y., a corporation The present invention relates to vapor generators and more particularly to pressurized vapor generators.

In pressurized vapor generators and more particularly those which have cylindrical shaped casings wherein the iluid conducting tubular members are circumferentially arranged in concentric rows, compactness and accessibility to the tubular members are problems of some magnitude. 1t is generally desired in the construction of such vapor generators to provide structure which embodies tubular members or heating surfaces arranged symmetrically in a compact arrangement and in a manner so that each tubular member receives similar amounts of heat. Necessarily such arrangements present problems of accessibility to the tubular members in the event of failure or burn-out of the latter.

The present invention has for an object the provision of a pressurized vapor generator which is highly efficient in operation, compact in structure, and wherein the heating surfaces or tubular members are readily accessible.

The present invention, therefore, contemplates a novel vapor generator which comprises a cylindrically shaped casing having a similar shaped combustion chamber therein. Vapor generating tubular members are arranged in the combustion chamber in concentric rows and the tubular members are spaced along a circumferential portion thereof in a manner to provide flow of combustion gases radially outward from the combustion chamber. A bank of superheater tubes is arranged in the casing in a manner whereby the radially flowing gases traverse the superheater tubes and thereafter pass in contact with a second group of vapor generating tubes positioned in an annular gas passage concentric with the combustion chamber. The superheater tubes are so constructed and arranged in the cylindrical casing as to render them readily accessible from outside the casing.

The invention will be understood from the following description when considered in connection with the accompanying drawings in which:

Fig. l is an elevational View, partly in section, of a vapor generator embodying the present invention;

Fig. 2 is a transverse sectional View taken along the line 2 2 of Fig. 1;

Fig. 3 is a partly diagrammatic representation, in plan, of the arrangement of the superheater tubes of Fig. l; and

Fig. 4 is an elevational view of a portion of the superheater of Fig. 1.

Referring now to the drawings and more particularly to Fig. 1 thereof, the numeral 11 generally designates a vapor generator, which comprises a vertically disposed boiler 12 and a horizontal vapor and liquid vessel or drum 13 disposed outside of boiler 12 and above the top thereof. Boiler 12 includes an upright cylindrical shell or casing 14 which is provided with an inner circular metal partition or baille 15 spaced from the casing and concentric therewith. Batlle 15 defines a combustion chamber 16 which has a refractory iloor portion 17 spaced from the lower edge of the baille. A circumferential row 18 of 2,854,961 Patented Get. 7, 1958 substantially vertical vapor generating tubes 19 is arranged adjacent the inner wall surface of bale 15 as to the line the latter. A second row 20 of vapor generating tubes 19 is arranged concentrically with row 18 and on the sides of tubes 19 of row 18 facing the combustion chamber. Tubes 19 of row 18 are spaced so as to partially accommodate therebetween tubes 19 of row 29. Tubes 19 of rows 18 and 20 are substantially vertically except at the upper portions thereof where the tubes are bent outwardly toward the axis of the combustion chamber 16 thence inwardly toward, and connected to, an upper circular outlet header 21, rectangular in transverse cross-section The lower portions of tubes 19 are inclined toward the axis of the combustion chamber for a short distance, whence the tubes then bend to extend substantially parallel to the combustion chamber axis. The lower ends of tubes 19 are secured to a lower circular header 22 coaxial with the combustion chamber and upper header 21. The lower portions of tubes 19 are spaced apart to provide a gas outlet 23 for passage of combustion gases from chamber 16; burners 24 being disposed at the top of casing 14 and tiring downwardly into chamber 16.

A second circular partition or baille 26 is arranged in casing 14 concentric with baille 15 to dene an annular gas passage 27 therebetween. Gas passage 27 has provided therein a plurality of substantially vertical vapor generating tubes 29 (Figs. 1 and 2) arranged in circular rows concentric with bailles 15 and 26. The upper end portions of vapor generating tubes 29 are secured to the bottom of circular outlet header 21; the lower portions of tubes 29 are slightly inclined in a direction away from the axis of the combustion chamber 16 whence the tubes extend vertically and parallel to the lower portions of tubes 19 adjacent gas outlet 23. The lower ends of tubes 29 are secured to a second lower circular inlet header 31), rectangular in transverse cross-section, which is arranged concentric with inlet header 22. The lower portions of vapor generating tubes 19 and 29 define therebetween an annular space 31 which communicates combustion chamber 16 with annular gas passage 27 so as to provide for passage of combustion gases from the chamber to the passage. A gas discharge port 32 is provided in casing 14 and communicates with gas passage 27 for discharging combustion gases from boiler 12.

Disposed in space 31, which is traversed by combustion gases flowing through chamber 16 to gas passage 27, is a superheater 34 which comprises sixteen horizontal layers of superheater tubes; each layer consisting of three circular arranged tubes. The layers bear the reference characters from 35 to 50 (Fig. 4) and the tubes in each layer are designated by the reference character of such layer together with the suil'x A, B or C. Considering the uppermost layer 35 for example, the layer (Fig. 3) consists of superheater tubes 35A, 35B and 35C, shown diagrammatically by broken center lines to more clearly illustrate the arrangement. The vertical portions of all superheater tubes however are shown in full lines. superheater tubes 35A, 35B and 35C are shaped in the form of spirals which commence at an imaginary circle 52 (shown as a full thin line in Fig. 3) and the initial points ofthe spirally wound tubes are spaced approximately apart on the circle. Each tube makes substantially two complete turns and the final points of the spirals terminate at an outer imaginary circle 54 (shown as a full thin line) which is concentric with circle 52; the terminal points of the spirals being spaced approximately 120 apart. The next succeeding layers 36 to 50 have their initial and nal points of their spirals on concentric inner and outer imaginary circles, respectively, as in the case of the ilrst layer. In proceeding toward the lowermost layer each succeeding layer has initial and nal points of the spirals on imagi- A circular inlet superheater header 56 and alcirculary outlet superheater header 53, respectively (Figi l) are positioned outside and below casing 14. headers 56 and 58 are arranged coaxial with each other and have secured thereto the opposite ends of the superheater tubes which extend substantially vertical in an upward direction from the headers (Fig. l). The superheater tubes extend through an annular closure plate 60 and in the space between headers 22 and 30 whence the tubes are bent to merge with the horizontal spiral portions of the tubes in the horizontal layers. The arcuate distances between the ends of the tubes in headers 56 and 58 are equal and the distances between the points where the tubes enter the horizontal layers for travel in their spiral paths are equal. It is readily apparent therefore, that the distances between such points are a function of the number of superheater tubes employed in the superheater 34. The length of each superheater tube is substantially the same exceptv for their vertical portions and consequently, the pressure drop and ow of steam in each tube is the same.

It is also apparent therefore that the heat absorption for every tube is identical, since the gas flow across the tubes and the arrangement of the tubes with respect to gas flow is perfectly symmetrical.

Interposed between the superheater tubes of superheater 34 are horizontal and vertical spacer rods 61 and 62 (Fig. 4), respectively. An upper annular plate 63 is provided on the uppermost layer 35 of superheater tubes and the plate has curved flanged portions 64 which grip the innermost and outermost portions of the spiral shaped superheater tubes 35A, 35B and 35C. A supporting lower annular plate 65 is provided for the lowermost layer 50 of superheater tubes and is secured to a circular and vertical supporting baille or rib member 66 which in turn is secured to annular closure plate 60.

A plurality of downcomers 68 are secured at their upper ends to the bottom of drum 13 to communicate with the water space of the latter. The other ends of downcomers 68 have reduced diameter portions and branch connections 69 which extend below the bottom of casing 14 and normal to the downcomers for connection to inner inlet header 22. As indicatedhereinbefore, both vapor generating tubes 19 and 29 are secured to upper outlet header 21 to thereby communicate inlet headers 22 and 30 with outlet header 21. Avplurality of riser conduits 70 are connected at their lower ends to outlet header 21 and at their upper ends to the bottom portion of drum 13 to communicate the header 21 with the water space in drum 13. A superheater conduit 72 is secured at one end to the upper portion of drum 13, as to be in communication with the steam space thereof, and the conduit is connected at the other end to the inlet superheater header 56.

In operation, burners 24 are supplied with fuel and combustion air underpositive pressure through conduits (not shown) and the burners direct ignited fuel downwardly into combustionchamber 16. The combustion gases ilow radially outward from the combustion chamber through gas outlet 23, thence over the superheaterv tubes of superheater 34 in passage 31. In passagel 31,

the combustion gases enter annular gas passage 27 for' flow upwardly therein and the gases then ow out of the passage in casing 14 through gas outlet port- 32. The water in drum 13 ows downwardly through downcomer conduits 68 and through the reduced diameter portions and, branch connections 69 into inner and outer inlet headers 22 and 30. From headers 22 and 30 the water ows upwardly through tubes 19. and 29 where a steam superheater. p

and water mixture is formed which then ows from the tubes into outlet header 21. The steam and water mixture then passes from header 21 through riser tubes 70 for collection in drum 13. The steam in drum 13 ows into the upper portion or steam space of the latter whence it is conducted by conduit 72 into inlet superheater header S6. The steam in header 56 passes through the vertically extending portions of the superheater tubes of superheater 34 for travel in the spiral formed portion of the tubes and the superheated steam then ows through the outlet portions of the tubes for collection in outlet superheater header 58. From header 58 the superheated steam is conducted by means (not shown) to steam utilization apparatus.

By reason of the foregoing construction, it is apparent that a compact vapor generator is provided and one in which the iluid contacting tubular members are readily accessible from outside the boiler casing. In the event that some of the superheater tubes rupture or fail, closure plate 60 may be removed andthe entire superheater assembly may be moved downwardly and out of the boiler casing 14. It may be readily understood that by positioning the superheater assembly in a location where it comes into contact with the combustion gases immediately upon leaving the combustion chamber, hotter gases are provided to effect increased thermal eiciency.

Although but one embodiment of the invention has been illustrated and described in detail, it is to be expressly understood the invention is not limited thereto. Various changes may be made in the design and arrangement of the parts without departing from the spirit and the scope of the invention as the same will now be understood by those skilled in the art.

What is claimed is:

l. In a vapor generator, means forming a substantially cylindrical combustion chamber having a longitudinal axis, burner means disposed for tiring into said combustion chamber to produce combustion gases, a plurality of circumferentially arranged vapor generating tubes lining the combustion chamber and having their axes extending in directions substantially parallel to the longitudinal axis of the combustion chamber except at a circumferential portion thereof where the tubes are bent toward said axis of the combustion chamber, said vapor generating tubes being subjected to the combustion gases in said chamber and being spaced apart at said circumferential portion to provide a gas outlet for said chamber, means forming an annular gas passage concentric with said combustion chamber and coextensive with the latter, a plurality of circumferentially arranged second vapor generating tubes arranged in said annular gas passage and extending in directions substantially parallel to the longitudinal axis of the combustion chamber except at a circumferential portion thereof where the tubes are bent away from said axis of the combustion chamber, said bent portions of said second vapor generating tubes being spaced apart adjacent said gas outlet to define with the bent portions of the first vapor generating tubes an entrance space to provide for passage of combustion gases from the gas outlet into said entrance space for flow into said annular gas passage, and a plurality of superheater coiled tubes encircling the combustion chamber disposed in the entrance space and arranged in the path of ow of the combustition gases flowing from said gas outlet to said annular gas passage, said superheater tubes being arranged in a plane which extends transversely of said axis of the combustion chamber and of the rst and second vapor generating tubes.

2. In a vapor generator, means forming a substantially cylindrical vertical combustion chamber having a longitudinal axis, burner means disposed for tiring into said combustion chamber to produce combustion gases, a plurality of circumferentially arranged upright vapor generating tubes lining the combustion chamber and being bent toward said axis. of the combustion chamber at a circumferential portion thereof, said vapor generating tubes being subjected to the combustion gases in said furnace and being spaced apart at said circumferential portion to define a gas outlet for said chamber, means forming an annular gas passage concentric with said combustion chamber and co-extensive with the latter, a plurality of circumferentially arranged upright second vapor:

generating tubes in said annular gas passage and bent away from the longitudinal axis of the combustion chamber along a circumferential portion thereof, said bent portions of said second vapor generating tubes being spaced apart adjacent said gas outlet to define with the bent portions of the vapor generating tubes an entrance space to provide for passage of combustion gases from the gas outlet into said entrance space for flow into said annular gas passage, and a plurality of superheater coiled tubes encircling the combustion chamber arranged horizontally in the entrance space and disposed in the path of flow of said combustion gases flowing from said gas outlet to said annular gas passage.

3. The vapor generator of claim 2 wherein the superheater circular tubes are substantially coaxial with the combustion chamber.

4. In a vapor generator, a vertical casing, means forming a vertical and cylindrical combustion chamber in said casing, burner means disposed for tiring into said com bustion chamber to produce combustion gases, a plurality of substantially upright vapor generating tubes lining the combustion chamber and extending from the top of said casing to the bottom thereof, said vapor generating tubes being subjected to the combustion gases, means forming an annular gas passage concentric with said combustion chamber and co-extensive therewith, a plurality of substantially upright second vapor generating tubes arranged in said annular gas passage in rows substantially concentric with the rst-mentioned vapor generating tubes and extending from the top of said casing to the bottom thereof, said tirst-mentioned and said second vapor generating tubes being bent away from each other at the bottom of said casing to provide an entrance space therebetween, said first and said second vapor generating tubes further being spaced apart from their adjacent tubes to define a gas outlet for discharging gases from the combustion chamber into the entrance space and a gas inlet for introducing the discharged combustion gases into said annular gas passage, respectively, and a plurality of horizontal coiled superheater tubes arranged coaxial of and encircling the combustion chamber and disposed in the entrance space between the bent away portions of said irst and said second Vapor generating tubes.

5. In a vapor generator, a vertical and cylindrical shaped casing, means forming a vertical and cylindrical combustion chamber within and concentric with said casing, said combustion chamber having a longitudinal axis, burner means disposed for tiring into said combustion chamber to produce combustion gases, a plurality of substantially upright vapor generating tubes in said combustion chamber circumferentially arranged in concentric rows, said vapor generating tubes extending from the top of the casing to the bottom thereof and being substantially vertical except at the bottom of the casing where the tubes are bent toward the longitudinal axis of the combustion chamber and are spaced apart to define a gas outlet for the combustion chamber, means forming an annular gas passage concentric with the combustion chamber and coextensive therewith, a plurality of substantially upright second vapor generating tubes in said annular gas passage arranged in rows substantially concentric with the rows of the first-mentioned vapor generating tubes, said second vapor generating tubes extending from the top of the casing to the bottom thereof and being substantialiy vertical except at the bottom of the casing where the tubes are bent away from the longitudinal axis of the combustion chamber and are spaced apart to define a gas inlet for introducing combustion gases discharged from the combustion chamber to the annular gas passage, the bent portions of said first and said second vapor generating tubes deiining a space therebetween, circular header means at the top of the casing connected to the upper ends of both rst and second vapor generating tubes, an annular header at the bottom of the casing and connected to the lower ends of the second vapor generating tubes, a second annular header spaced from and concentric with the last-mentioned header and connected to the lower ends of the first vapor generating tubes, and a plurality of horizontally arranged circular superheater tubes disposed in the space between the bent portions of the iirst and the second vapor generating tubes, each of said superheater tubes having a pair of end portions which extend vertically downwardly between said concentric headers and which project through the bottom of the casing.

6. In a vapor generator, a vertical and cylindrical shaped casing, means forming a vertical and cylindrical combustion chamber within and concentric with said casing, said combustion chamber having a longitudinal axis, burner means disposed for tiring into said combustion chamber to produce combustion gases, a plurality of substantially upright vapor generating tubes in said combustion chamber circumferentially arranged in concentric rows, said vapor generating tubes extending from the top of the casing to the bottom thereof and being substantially vertical except at the bottom of the casing where the tubes are bent toward the longitudinal axis of the combustion chamber and are spaced apart to deline a gas outlet for the combustion chamber, means forming :an annular gas passage concentric with the combustion chamber and co-extensive therewith, a plurality of substantially upright second vapor generating tubes in said annular gas passage arranged in rows substantially concentric with the rows of the first-mentioned vapor generating tubes, said second vapor generating tubes extending from the top of the casing to the bottom thereof and being 4substantially vertical except at the bottom of the casing where the tubes are bent away from the longitudinal axis of the combustion chamber and are spaced apart to deline a gas inlet for introducing combustion gases discharged from the combustion chamber to the annular gas passage, the bent portions of said rst and said second vapor generating tubes delining ya 4space therebetween, a vapor and liquid vessel outside said casing, a irst annular header forming part of the bottom of the casing and arranged coaxially of the combustion chamber, said iirst header having the lower ends of the rst vapor generating tubes secured thereto, a second annular header spaced from and concentric with the last-mentioned header and also forming part of the bottom of the casing, said second header having the lower ends of the second vapor generating tubes secured thereto, downcomer means outside said casing and communicating the liquid space of said vapor and liquid vessel with said rst and 4said second annular headers, a third annular header forming part of the top of said casing and coaxial with the tirst and the second headers, said third header having the upper ends of said first and said second vapor generating tubes connected thereto, riser conduits communicating said third header with the vapor and liquid Vessel, a plurality of 4horizontally disposed circular superheater tubes disposed in the space between the bent portions of the -iirst and second vapor generating tubes, an annular closure plate secured between said iirst and said second annular headers -and forming part of the bottom of the casing, each of said superheating tubes have ing an inlet end portion and an outlet end portion which extend vertically downwardly between said iirst and said second annular headers and project through said annular closure plate, a circular inlet superheater header disposed outside said casing and having the inlet end portions of the superheater tubes secured thereto, a circular outlet superheater header arranged outside said casing coaxial with the inlet superheater header and having the outlet end portions of the superheater tubes secured thereto, and a conduit communicating the vapor space of the vapor and liquid vessel with the inlet superheater header.

7. In a vapor generator, means forming a substantially cylindrical vertical combustion chamber having a longitudinal axis, burner means disposed for firing into said combustion chamber to produce combustion gases, a plurality of circumferentially arranged upright vapor generating tubes lining the combustion chamber and being bent toward the axis of the combustion chamber at a circumferential portion thereof, said vapor generating tubes being subjected to the combustion gases in said furnace and being spaced apart at said circumferential portion to define a gas outlet for said chamber, means forming an annular gas passage concentric with said combustion chamber and coextensive with the latter, a plurality of circumferentially arranged upright second vapor generating tubes in said annular gas passage and bent away from the longitudinal axis of the combustion chamber along a circumferential portion thereof, said bent portions of said second vapor generating tubes being spaced apart adjacent said gas outlet and providing for passage of combustion gases from the latter into said annular gas passage, a superheater assembly arranged in the space between the bent away portions of said first and said second vapor generating tubes and `disposed in the path of flow of said combustion gases flowing through said gas outlet to said annular gas passage, the superheater assembly comprising a plurality of horizontally disposed layers of superheater tubes extending substantially coaxial of the combustion chamber, each layer having a plurality of coplanar tubes substantially equal in length and each tube being arranged in the form of .a spiral, the initial portions of the spirals of one layer commencing at an imaginary circle and the final portions of said spirals terminating at an outer imaginary circle concentric with the inner circle,

the distance between the initial and final portions of each.

spiral on the circles being a function of the number of tubes in a layer, said tubes each having a pair of vertically extending end portions substantially normal to the horizontal portions of the tubes and -constituting the inlet and outlet rsepectively of said tubes, an annular superheater inlet header arranged outside said casing `and having the inlet end portions of the superheated tubes connected thereto, and an annular superheater outlet header outside said casing and coaxial with the superheater inlet header, said superheater outlet header having the outlet end portions of said superheater tubes connected thereto.

8. The vapor generator of claim 7 wherein the inner and outer superheater headers have diameters equal to the inner and outer imaginary circles, respectively.

9. A superheater assembly comprising a plurality of horizontally disposed layers 4of tubes, each layer having a plurality of coplanar tubes substantially equal in length and each tube being arranged in a form of a spiral, the initial portions of the spirals commencing at an imaginary inner circle and the final portions of said spirals terminating at an outer imaginary circle concentric with the inner circle, the distance between the initial and final portions of each spiral on the circles being a function of the numf ber of tubes in a layer, said tubes each having a pair of vertically extending end portions normal to the horizontal portions of the tubes and constituting the inlet and outlet, respectively -of said tubes, an annular superheater inlet header coaxial with the imaginary circles and having the inlet end portions of the tubes secured thereto, and an outlet superheater header coaxial with the imaginary circles and the inlet superheater header and having the outlet end portions of the tubes connected thereto.

10. ln a vapor generator, a vertical and cylindricalshaped casing, means forming a vertical and cylindrical combustion chamber within and concentric with said casing, said combustion chamber having a longitudinal axis, burner means disposed for firing into said combustion chamber to produce combustion gases, a plurality of substantially upright vapor generating tubes in said combustion chamber circumferentially arranged in concentric rows, said Vapor generating tubes extending from the top of the casing to the bottom thereof and being substantially vertical except at the bottom of the casing where the tubes are bent toward the longitudinal axis of the combustion chamber and are spaced apart to define a gas outlet 'for the combustion chamber, means forming an annular gas passage concentric with the combustion chamber and coextensive therewith, a plurality of substantially upright second vapor generating tubes in said annular gas passage arranged in rows substantially concentric with the rows of the first-mentioned vapor generating tubes, said second vapor generating tubes extending from the top of the casing to the bottom thereof and being substantially vertical except at the bottom of the casing where the tubes are bent away from the longitudinal axis of the combustion chamber and are spaced apart to define a gas inlet for introducing combustion gases discharged from the combustion chamber to the annular gas passage, the bent portions of the said first and said second vapor generating tubes defining a space therebetween, a plurality of horizontally arranged circular superheater tubes disposed in the space between the bent portions of the rst and second vapor generating tubes, a closure plate for the bottom of the casing and for supporting the superheater tubes, each of said superheater tubes having ends which extend through said bottom closure plate, an annular inlet superheater header disposed below the bottom closure plate for connection to a portion of the tube ends of the superheater, and a second annular superheater outlet header coaxial with the first superheater header and having the remaining ends of the superheater tubes connected thereto.

References Cited in the file of this patent UNlTED STATES PATENTS 

